on his side
Tal vez el destino estaba ahora de su lado.
Perhaps fate was on their side now.
— Bhaag Milkha Bhaag (2013)
We are on your side.
Me puse de su lado en la discusión.
I sided with him in the argument.
Estoy de su lado, Sr. Frodo.
I'm on your side, Mr. Frodo.
— El señor de los anillos: El retorno del rey (2003)
Yo estuve de su lado aún en contra de mi padre.
I was on his side even against my father.
I'm on your side.
Obviamente él es tu amigo te vas a poner de su lado.
Obviously, he's your friend, so you're going to take his side.
— Piku (2015)
Y la verdad está de su lado, amigo.
And the truth is on your side, my friend.